The present invention relates in general to non-linear elements, and more specifically, to symmetrically programmable resistive synapse for a resistive processing unit (“RPU”) using current-programmed single domain wall ferroelectrics.
Ferroelectric materials are characterized by a finite electric polarization in the absence of an external electric field. This polarization must possess at least two stable states, and must have the ability to be reversibly switched from one state to another by the application of an electric field. Thus, regions with different orientations of the polarization vector can coexist within a ferroelectric sample, and these regions are called ferroelectric domains. Ferroelectric domain walls are close to atomically sharp topological defects that separate regions of uniform polarization. The discovery of electrical conductivity in specific types of walls gave rise to “domain wall nanoelectronics,” a technology in which the wall (rather than the domain) stores information.